1. Field of Invention
The present invention relates to an electrical joint connector suitable to be incorporated in a wire harness to be placed on a vehicle body, such as an automobile body, and to an assembly of the joint connector and exterior connectors.
2. Description of Related Art
In a wire harness to be wired in a vehicle body, if a splice treatment of the wiring cannot be made in an internal circuit of a junction box or the like, a joint connector is connected to the electrical wiring to make the splice. A joint connector 1 having the construction shown in FIG. 8 is used normally for this kind of purpose.
The joint connector 1 accommodates joint bus bars 3, each having a tab 3a, provided in a casing 2. Terminals connected to the ends of the wires W branching from a wire harness W/H are inserted into a mating connector 4 and locked in position, and the connector 4 is inserted into a receiving opening 1a of the joint connector 1 and locked thereto to connect the connector 4 to the joint connector 1. In this manner, the electrical wires W are connected at the joint connector 1. The joint connector 1 and the connector 4 connected to each other are fixed to the wire harness W/H with a tape.
The tabs 3a of the joint bus bars 3 are oriented in the same direction. In addition, the joint connector 1 has only one receiving opening 1a for the mating connector 4. Therefore, the mating connector 4 can be inserted from only one direction into the joint connector 1. For example, referring to FIG. 9, if it is necessary to connect wires of a trunk wire harness W/H-1 to a group of wires of a branch wire harness W/H-2 and a group of wires of a branch wire harness W/H-3, still only one mating connector 4 is connected to the joint connector 1, as described above. Therefore, the electric wires to be spliced are necessarily placed into one wire harness W/H and connected to the joint connector 1 as shown in FIG. 8 or two joint connectors are prepared to splice the wires. Accordingly, it is impossible to make an optimum design of the wire harness to be connected to the joint connector. Further, the position of installation of the joint connector is restricted. As such, the joint connector cannot be disposed at an optimum position in an installation space.
Furthermore, because the joint connector 4 has two superimposed rows of terminals, it is voluminous. Thus, when the joint connector is installed on the trunk wire harness, e.g. taped up with the harness, the shape of the wire harness becomes irregular. Projecting portions are liable to be caught by other component parts when installing the trunk wire harness on a vehicle body. Consequently, wiring operability is poor. For example, paths for the trunk wire harness cannot be secured or the trunk wire harness cannot be inserted through a through-hole of a body panel.
In addition, in the case where branch connectors to be connected to respective joint connectors have the same configuration, an erroneous connection may be made. To prevent such an erroneous connection, various countermeasures are made. For example, the colors of the connectors are varied. However, when the lengths of the branch wires are equal to each other, it is impossible to securely prevent the erroneous connection.
It is an object of the present invention to provide a joint connector for a wire harness, which can be connected to mating connectors in a plurality of directions, allow an optimum division of a wire harness, be of small volume and thus be installed at an optimum position in the space of a vehicle body, and reduce the occurrence of erroneous connection.
According to the invention, there is provided a joint connector for connection to first, second and third exterior electrical connectors to effect electrical connection between the first exterior connector and each of the second and third exterior connectors. The joint connector has an insulation plate having opposite first and second main faces.
A plurality of first elongate bus bars are mounted on the first main face and extend in parallel in a first direction. First end portions of the first bus bars constitute a set of first connection tabs.
A plurality of second elongate bus bars are mounted on the second main face of the insulation plate and extend parallel in a second direction crossing the first direction, so that the first and second bus bars, as seen in plan view on one of the main faces of the insulation plate, form a lattice array having intersection points of the bus bars. Second and third end portions of the second bus bars, respectively at opposite ends of the second main face, constitute respectively a set of second connection tabs and a set of third connection tabs. The first and second bus bars are electrically joined to each other at a plurality of the intersecting points through holes in the insulation plate to form a predetermined interior circuit in the joint connector.
A casing of flat shape accommodates the insulation plate and the first and second bus bars, and has first, second and third connector-receiving locations at which the exterior connectors can be fitted to make electrical connection. The first connection tabs are located in the first connector-receiving location to connect to the first exterior connector, and the sets of second and third connector tabs are located respectively in the second and third connector-receiving locations, which are on opposite sides of the casing, to connect to the second and third exterior connectors respectively.
The interior circuit is such that the circuit connections from the first connection tabs to the set of second connector tabs and the set of third connector tabs respectively are identical. This allows the second and third connectors to be interchangeably attached at the second and third connector-receiving locations, so that erroneous connection can be avoided.
Preferably the second and third connector-receiving locations have substantially identical shape and configuration but are mutually inverted with respect to the casing, while the first connector-receiving location has a substantially different shape and configuration.
The above construction allows the connector-receiving locations to be formed in different directions. For example, the first location may be on a side of the casing perpendicular to the two opposite sides of the second and third locations, so that the casing is T-shaped. Accordingly, it is unnecessary to bundle electric wires to be spliced through the joint connector into one wire harness, but it is possible to design a circuit according to a wiring configuration of the wire harness and according to where a space for the joint connector is located. Consequently, it is possible to accomplish an optimum division of the wire harness.
Preferably, the first and second bus bars are bent downward and upward respectively at their portions connected through holes in the insulation plate. Then, the apex of the bent portion of the first bus bar and that of the bent portion of the second bus bar are brought into contact in the through-hole of the insulation plate. In this state, resistance welding is carried out to connect the bus bars to each other. It is possible to weld bus bars laminated one upon another in three or more layers.
The insulation plate has the bus bars disposed on its upper and lower surfaces. Thus, it is possible to accommodate the plate in a low, flat casing. Thus, the joint connector is not voluminous. Therefore, when the joint connector is installed on the peripheral surface of the trunk electric wire of the wire harness, this portion of the wire harness does not project much, which facilitates an operation of wiring the wire harness on a vehicle body.